1. Field of the Invention
This invention relates generally to floating offloading and storage facilities for subsea hydrocarbon products, and more particularly to such offloading and storage facilities utilizing an offloading mooring buoy.
2. Description of the Prior Art
Offloading mooring buoys for shuttle tankers or other vessels have been used with floating production storage and offloading facilities, such as permanently moored storage tankers. Normally, the storage and offloading facility is connected directly to subsea product lines and receives product from subsea wells. In some locations, dependent on the various water depths and distances, an offloading mooring buoy may be located one thousand (1,000) to fifteen hundred (1,500) meters from a permanent floating storage facility. Shuttle tankers connect to the offloading mooring buoy to receive product therefrom for transport
Product flowlines or risers normally extend from the subsea wells to the permanent floating storage facility, and from the storage facility to the mooring buoy for connection to the shuttle tanker for transport. In the past, such product flowlines from the storage facility to the offloading mooring buoy, particularly where the offloading mooring buoy has been spaced a substantial distance from the storage facility, have comprised metal pipes with intermediate floatation devices located along the lengths of the product flowlines to provide a suitable contour or configuration to the flowlines to avoid excessive loads resulting from the weight of the flowlines and the relative motions of the offloading mooring buoy and the floating storage facility. The installation of such metal pipe on the offloading mooring buoy requires the lifting of large loads because of the weight of the pipe. Furthermore, it has been difficult to tow the pipe to the mooring buoy from the permanent storage facility because of the weight of the pipe and the substantial distances required for towing, such as fifteen hundred (1,500) meters.
Identification of Objects of the Invention
It is an object of the present invention to provide an improved installation system for the attachment of product flowlines between two floating facilities separated by a substantial distance over about five hundred (500) meters, for example.
A further object of the invention is to provide such an installation system for a floating storage facility utilizing a pipeline manifold connected to the flowlines from the storage facility and transported to an offloading mooring buoy for connection to the offloading mooring buoy.